To control supplying of pressurized fluid, such as liquid or gas, to an equipment to be supplied with the fluid, or to control pressurized fluid exhaust from the equipment, or further to control a process to switch communication passages, a solenoid valve which uses a valve member to open and close communication holes provided in a valve seat has been utilized.
In a two-port solenoid valve having a supply port communicating with a pressurized gas source and an output port communicating with an equipment to be supplied, the solenoid valve controls switching between a communicated state and a blocked state of the ports. On the other hand, in a three-port solenoid valve for gas having an exhaust port in addition to the supply port and the output port, the solenoid valve controls the switching between: a state in which the exhaust port is blocked of communication from the output port while the supply port is communicating with the output port, thereby supplying the pressurized gas to the output port; and a state in which the supply port is blocked of communication from the output port while the exhaust port is communicating with the output port, thereby discharging the pressurized gas which had returned to the output port to the outside through the exhaust port. Moreover, in a solenoid valve with ports for liquids which have one supply port to be supplied with pressurized liquid and two output ports for discharging the liquid to the outside, the solenoid valve controls the switching between: a state in which the liquid is supplied from the supply port to one of the output ports; and a state in which the supply port supplies the liquid to the other output port.
A solenoid which opens and closes the valve has a fixed iron core attached to a bobbin with a coil wound around and a movable iron core to be driven by an energized coil; thus, the valve member is driven by the movable iron core. The movable iron core is either axially movable or swingable. The axially movable iron core coaxially reciprocates in axial directions with the fixed iron core. On the other hand, the swingable movable iron core reciprocatively swings with one end portion of the movable iron core serving as the center.
Japanese Unexamined Patent Application Publication No. H08-330130 describes a solenoid valve having a swingable movable iron core. Japanese Unexamined Patent Application Publication No. 2000-297876, Japanese Unexamined Patent Application Publication No. 2004-144243 and Japanese Unexamined Patent Application Publication No. 2005-315326 describe solenoid valves having an axially movable iron core.